1. Field of the Invention
This invention relates to polyimides and their precursors. More specifically, this invention relates to polyimides, polyamides, and dianhydrides derived from trimellitic anhydride and adamantane diacetates.
2. Description of the Prior Art
A first patent issued to D. F. Loncrini, U.S. Pat. No. 3,182,073 (1965) discloses the preparation of polyanhydrides of the general formula ##STR1## in which A and B can be oxygen, R.sub.1 and R.sub.2 can be phenyl radicals, and R can be an alicyclic radical such as the divalent radical derived from cyclohexane, cyclobutane, cyclopentane, and the like.
A second patent also issued to Loncrini, U.S. Pat. No. 3,355,427 (1967), which incorporates the '073 patent by reference, discloses the preparation of polyamides and polyimides from diamines and the polyanhydrides disclosed in the '073 patent. Reference is broadly made to the use of alicyclic compounds mentioned in the '073 patent.
However, neither patent contains an enabling disclosure where an alicyclic compound is used to produce a dianhydride, a polyamide, or a polyesterimide. More specifically, the use of an adamantane derivative is not suggested. In fact, those alicyclic compounds which are cited as exemplary are all monocyclic compounds of the same homologous series and are structurally dissimilar to the adamantane derivatives. Because the geometry of the adamantane nucleus will not allow the formation of a double bond between the .alpha. and .beta. carbon atoms, adamantane derivatives are unique in that they cannot undergo ester pyrolysis which can readily occur with other alicyclic nuclei such as cyclohexane. This fact coupled with the marked structural difference between Applicant's compositions and those of the prior art are believed to give rise to desirable physical properties such as high heat stability. The polyesterimides are particularly useful for making films, coatings, and molded forms for use at elevated temperatures.
Accordingly, it is an object of this invention to produce a polyesterimide incorporating the adamantane nucleus which is useful for making films, coatings and molded forms for use at elevated temperatures.
It is a further object of this invention to produce a polyamide acid incorporating the adamantane nucleus which is useful in preparing temperature resistant polyesterimides.
It is a further object of this invention to produce a dianhydride incorporating the adamantane nucleus which is useful in preparing temperature resistant polyesterimides.